I don't think this has anything to do with race.
My gut instinct tells me that Gates was insulted that he was not recognized.
I think in his mind his own importance is over-inflated.
I think he perceives himself to be more famous than what he is.
My gut instinct tells me that Gates acted out of inflated ego and rather than admit that to himself, he is deflecting his embarassing arrogance into a racial thing because people are always hot for that sort of scandal.
Haven't you seen people puffed up with their own importance?
"What? Don't you know who I am? You can't do this to me!"
What would it have cost for Gates to be polite, cooperative, and appreciative of the security?
This was all about EGO....not race.